Bio-based synthesis of Nano-Ceria and evaluation of its bio-distribution and biological properties.

Bio-based synthesis of Nano-Ceria (NC) was performed in Linum usitatissimum L. (Lu) seeds extract as capping agent. Obtained gel was calcined at 400, 500, and 600 °C to investigate the effect of temperature on the size and morphology of the particles. All samples had spherical morphology which their crystallite size was decreased in higher temperature. Products were characterized by TGA/DTA, UV-vis, FESEM, FTIR and XRD. The band gap of the prepared samples was calculated through Tauc plot in the range of 3.2-3.4 eV. The results of MTT assay confirmed that NC has been shown no significant toxicity on A549 cell line. 2',7'-dichlorofluorescin diacetate (DCFDA) was used to determine antioxidant properties of NC on A549 cell and the results showed that all concentrations of NC could reduce reactive oxygen species (ROS). NC was labeled with technetium (99mTc) for in vivo bio-distribution study in Wistar rat. Radiolabeled NC was stable in different environments of PBS buffer and human serum with radiochemical purity of more than 95% according to the instant thin layer chromatography (ITLC) method. DLS analysis showed radiolabeled particles had small size and pleasant colloidal stability. Bio-distribution of radiolabeled NC illustrated the highest accumulation in kidneys (1 h: 5.94 ± 0.77%ID/g, 4 h: 10.95 ± 5.99%ID/g, 24 h 7.94 ± 0.36%ID/g). Moreover, low uptake of 99mTc-NC in stomach confirmed the in vivo stability of 99mTc-NC. Accordingly, NC could be a worthy candidate for biological purposes and in vivo studies.